os: replace PATH_SEP with std.fs.path.delimiter

This standard library symbol is equivalent.

src/os/env.zig

@@ -3,12 +3,6 @@ const builtin = @import("builtin");
 const Allocator = std.mem.Allocator;
 const posix = std.posix;
 
-/// The separator used in environment variables such as PATH.
-pub const PATH_SEP = switch (builtin.os.tag) {
-    .windows => ";",
-    else => ":",
-};
-
 /// Append a value to an environment variable such as PATH.
 /// The returned value is always allocated so it must be freed.
 pub fn appendEnv(
@@ -33,9 +27,9 @@ pub fn appendEnvAlways(
     current: []const u8,
     value: []const u8,
 ) ![]u8 {
-    return try std.fmt.allocPrint(alloc, "{s}{s}{s}", .{
+    return try std.fmt.allocPrint(alloc, "{s}{c}{s}", .{
         current,
-        PATH_SEP,
+        std.fs.path.delimiter,
         value,
     });
 }

src/os/main.zig

@@ -25,7 +25,6 @@ pub const windows = @import("windows.zig");
 // Functions and types
 pub const CFReleaseThread = @import("cf_release_thread.zig");
 pub const TempDir = @import("TempDir.zig");
-pub const PATH_SEP = env.PATH_SEP;
 pub const appendEnv = env.appendEnv;
 pub const appendEnvAlways = env.appendEnvAlways;
 pub const getenv = env.getenv;

src/termio/Exec.zig

@@ -780,7 +780,7 @@ const Subprocess = struct {
             // then we just set it to the directory of the binary.
             if (env.get("PATH")) |path| {
                 // Verify that our path doesn't already contain this entry
-                var it = std.mem.tokenizeScalar(u8, path, internal_os.PATH_SEP[0]);
+                var it = std.mem.tokenizeScalar(u8, path, std.fs.path.delimiter);
                 while (it.next()) |entry| {
                     if (std.mem.eql(u8, entry, exe_dir)) break :ghostty_path;
                 }